The use of medical imaging equipment is prevalent throughout the medical field.
For instance, in interventions such as catheter introductions, X-ray imaging apparatuses of the C-arm type are sometimes used to obtain imagery of the patient's internal configuration to ensure proper localization of the catheter or other medical tool.
To get best results, images are acquired from a number of different viewing directions. To be able to do this, an X-ray source and/or detector of the imaging apparatus is mounted on a moveable gantry, also called a C-arm, which rotates round the patient to acquire the X-ray imagery. In some scenarios, these rotations are carried out whilst medical personnel is present close to the patient and/or close to the imaging apparatus itself.
It is not uncommon for collisions to occur, for instance, personnel is hit by the C-arm or surrounding equipment may be damaged if left inadvertently unsuitably placed in the C-arm's path.
To mitigate these situations some modern X-ray imagers use anti-collision systems. In these systems, proximity sensors are used to detect proximity of objects to the C-arm and a collision avoidance action is taken, such as the C-arm is slowed down or its motion is even brought to a halt.
Experience has shown however that performance of these anti-collision-systems under real conditions is often unsatisfactory. In particular, it has been observed that these systems sometimes produce an unacceptable number of “false positive” or “false negative” results: for instance the system fails to take the necessary collision avoidance action as it reached the conclusion that no object was present although there was. Or it happens that the system is overly cautious and hampers efficient use of the medical equipment. The anti-collision action is taken although there is no danger of collision. The system erroneously concluded that there was an obstacle although in reality there was not.
An exemplary imaging system with collision avoidance is described in Applicant's U.S. Pat. No. 5,570,770.